11642( 4) - 24-Sep-2008 10:31:36 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 11642 Version: 4 Check-in Time: 24-Sep-2008 10:31:36 STScI Edit Number: 1 Title FUV/X-ray absorption and emission line spectroscopy of the Galactic corona ------------------------------------------------------------------------------------ Type Cycle GO 17 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Yangsen Yao University of Colorado at Boulder CoI: Prof. Q. Daniel Wang University of Massachusetts N CoI: Prof. Todd M. Tripp University of Massachusetts N ------------------------------------------------------------------------------------ Abstract The Galactic corona is believed to play an essential role in the ``ecosystem'' of the Galaxy. But the extent and ionization state as well as the physical properties of the corona are yet to be determined. We request COS/HST observations to sample the intervening gas through the line absorptions of CIV, NV, SiIV, OI, SII, SiII, and FeII along the LMC X-3 sight line, toward which we have already detected OVI, OVII, and NeIX absorption lines and NVII, OVII, OVIII, and NeIX emission lines with FUSE, Chandra, and Suzaku observations. We have developed a software tool to jointly analyze the far-UV/X-ray absorption and emission spectra. The requested observations will not only allow us to rigorously test our preliminary results based on the existing observations, but also enable us to examine various models (e.g., diffuse hot gas vs. conductive layers) and to constrain the spatial and thermal properties of the hot gas over a broad temperature range. The results will p! rovide a unique calibration of our understanding of the corona. ------------------------------------------------------------------------------------ Observations Description ------------------------ The main goals of this project are to test our preliminary results based on a multiwavelength campaign and to investigate the spatial and thermal properties of the Galactic hot gas. To this end, we seek to obtain high resolution spectra of LMC X-3 covering the high ionization as well as the low ionization species. Our previous studies predict column densities of C IV and N V to be 6E13 and 2.2E13 cm^-2, respectively, contained in the hot diffuse gas toward the LMC X-3 sight line. Detecting these lines is our fundamental requirement and also drives the requested S/N level. LMC X-3 is mildly variable in UV wavelength band. We therefore use a spectrum with a typical flux obtained from one of the previous IUE observations as the input to the Exposure Time Calculator to estimate the ACQ-target-searching and ACQ-target-imaging time and to calculate the Buffer-time. The approved 7 orbits are split into two visits, in which the first 6 orbits use the COS/G130 grating to detect the N V absorption line while the seventh orbit uses the COS/G160 to detect the C IV line. With this exposure allocation, we expect to obtain a spectrum with S/N of 35 and 11 around N V and C IV wavelengths, respectively, which allows us to to detect these lines at >5sigma significant levels (with the expected column densities). 11642( 4) - 24-Sep-2008 10:31:36 - [ 2] To reduce COS fixed-pattern noise but also to minimize the overhead times associated with the OSM movement at the same time, we use a grating at different central wevelengths in successive exposures to mimic the different FP-POS offsets. By doing this, we will also obtain a spectrum coving the entire wavelength range; the gaps at different wavelengths are also filled up with nearly even exposures. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 11642( 4) - 24-Sep-2008 10:31:36 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 X-LMC-X-3 EXT-STAR, B3-B5 V-IV, RA=05H38M56.2300S +/- 0.1", J2000 V = 17.2 MXB DEC=-64D05'2.80" +/- 0.1" Reference Frame: ICRS Comments: This object was generated by the targetselector and retrieved from the SIMBAD database. ------------------------------------------------------------------------------------------------------------------------------------ 11642( 4) - 24-Sep-2008 10:31:36 - [ 4] Visit: 01 Visit Requirements: ORIENT 135D TO 95 D On Hold Comments: Additional Comments: Find a UV source from the Galex survey, which may confuse the proposed target. So a visit orientation constraint is requested to exclude that source from the BOA. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 X-LMC-X-3 COS/NUV ACQ/SEA PSA MIRRORB SCAN-SIZE=3, STEP-SIZE=1.767 1 38 S RCH Comments: COS84126 ------------------------------------------------------------------------------------------------------------------------------------ 2 X-LMC-X-3 COS/NUV ACQ/IMA PSA MIRRORB 1 38 S GE ------------------------------------------------------------------------------------------------------------------------------------ 3 X-LMC-X-3 COS/FUV TIME-TA PSA G130M 1318 BUFFER-TIME=2141 1 2141 S G Comments: COS84127 ------------------------------------------------------------------------------------------------------------------------------------ 4 X-LMC-X-3 COS/FUV TIME-TA PSA G130M 1309 BUFFER-TIME=2740 1 3270 S G Comments: COS84129 ------------------------------------------------------------------------------------------------------------------------------------ 5 X-LMC-X-3 COS/FUV TIME-TA PSA G130M 1300 BUFFER-TIME=2340 1 3270 S G Comments: COS84130 ------------------------------------------------------------------------------------------------------------------------------------ 6 X-LMC-X-3 COS/FUV TIME-TA PSA G130M 1291 BUFFER-TIME=2340 1 3270 S G Comments: COS84130 ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ X-LMC-X-3 1 COS/NUV ACQ/SEA PSA MIRRORB none none none none 1 N/A RCH X-LMC-X-3 2 COS/NUV ACQ/IMA PSA MIRRORB none none none none 1 N/A GE X-LMC-X-3 3 COS/FUV TIME-TA PSA G130M 1318 none none none none 1 N/A G X-LMC-X-3 4 COS/FUV TIME-TA PSA G130M 1309 none none none none 2 N/A G X-LMC-X-3 5 COS/FUV TIME-TA PSA G130M 1300 none none none none 3 N/A G X-LMC-X-3 6 COS/FUV TIME-TA PSA G130M 1291 none none none none 4 N/A G 11642( 4) - 24-Sep-2008 10:31:36 - [ 5] Visit: 02 Visit Requirements: ORIENT 135D TO 95 D On Hold Comments: Additional Comments: Find a UV source from the Galex survey, which may confuse the proposed target. So a visit orientation constraint is requested to exclude that source from the BOA. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 X-LMC-X-3 COS/NUV ACQ/SEA PSA MIRRORB SCAN-SIZE=3, STEP-SIZE=1.767 1 38 S RCH Comments: COS84126 ------------------------------------------------------------------------------------------------------------------------------------ 2 X-LMC-X-3 COS/NUV ACQ/IMA PSA MIRRORB 1 38 S GE Comments: COS84126 ------------------------------------------------------------------------------------------------------------------------------------ 3 X-LMC-X-3 COS/FUV TIME-TA PSA G130M 1318 BUFFER-TIME=944 1 944 S G Comments: COS84133 ------------------------------------------------------------------------------------------------------------------------------------ 4 X-LMC-X-3 COS/FUV TIME-TA PSA G130M 1309 BUFFER-TIME=941 1 941 S G Comments: COS84133 ------------------------------------------------------------------------------------------------------------------------------------ 5 X-LMC-X-3 COS/FUV TIME-TA PSA G130M 1300 BUFFER-TIME=1507 1 1507 S G Comments: COS84135 ------------------------------------------------------------------------------------------------------------------------------------ 6 X-LMC-X-3 COS/FUV TIME-TA PSA G130M 1291 BUFFER-TIME=1507 1 1507 S G Comments: COS84135 ------------------------------------------------------------------------------------------------------------------------------------ 7 X-LMC-X-3 COS/FUV TIME-TA PSA G160M 1589 BUFFER-TIME=575 1 675 S G Comments: COS84136; using exposure time - 100 s. ------------------------------------------------------------------------------------------------------------------------------------ 8 X-LMC-X-3 COS/FUV TIME-TA PSA G160M 1600 BUFFER-TIME=575 1 675 S G Comments: COS84136; using exposure time - 100 s. ------------------------------------------------------------------------------------------------------------------------------------ 9 X-LMC-X-3 COS/FUV TIME-TA PSA G160M 1611 BUFFER-TIME=575 1 675 S G Comments: COS84136; using exposure time - 100s. ------------------------------------------------------------------------------------------------------------------------------------ 10 X-LMC-X-3 COS/FUV TIME-TA PSA G160M 1623 BUFFER-TIME=575 1 675 S G Comments: COS84136; using exposure time - 100s. ------------------------------------------------------------------------------------------------------------------------------------ 11642( 4) - 24-Sep-2008 10:31:36 - [ 6] Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ X-LMC-X-3 1 COS/NUV ACQ/SEA PSA MIRRORB none none none none 1 N/A RCH X-LMC-X-3 2 COS/NUV ACQ/IMA PSA MIRRORB none none none none 1 N/A GE X-LMC-X-3 3 COS/FUV TIME-TA PSA G130M 1318 none none none none 1 N/A G X-LMC-X-3 4 COS/FUV TIME-TA PSA G130M 1309 none none none none 1 N/A G X-LMC-X-3 5 COS/FUV TIME-TA PSA G130M 1300 none none none none 2 N/A G X-LMC-X-3 6 COS/FUV TIME-TA PSA G130M 1291 none none none none 2 N/A G X-LMC-X-3 7 COS/FUV TIME-TA PSA G160M 1589 none none none none 3 N/A G X-LMC-X-3 8 COS/FUV TIME-TA PSA G160M 1600 none none none none 3 N/A G X-LMC-X-3 9 COS/FUV TIME-TA PSA G160M 1611 none none none none 3 N/A G X-LMC-X-3 10 COS/FUV TIME-TA PSA G160M 1623 none none none none 3 N/A G 11642( 4) - 24-Sep-2008 10:31:36 - [ 7] Summary Form for Proposal 11642 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures PSA ------------------------------------------------------------------------------------------------------------------------------------ Configurations COS/FUV, COS/NUV ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/IMAGE, ACQ/SEARCH, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BUFFER-TIME=1507, BUFFER-TIME=2141, BUFFER-TIME=2340, BUFFER-TIME=2740, BUFFER-TIME=575, BUFFER-TIME=941, BUFFER-TIME=944, SCAN-SIZE=3, STEP-SIZE=1.767 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 135D TO 95 D ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G130M, G160M, MIRRORB ------------------------------------------------------------------------------------------------------------------------------------ Target Names X-LMC-X-3 ------------------------------------------------------------------------------------------------------------------------------------